Chapter 19, Problem 9A

Summary Introduction

To write:

About if the current basis of classifying protists is correct or there could be any other basis.

Introduction:

Organisms belonging to the Kingdom Protista are eukaryotes. A eukaryotic organism or a eukaryotic cell is characterized by the presence of membrane-bound organelles and the presence of the 80S ribosome. Although these organisms are eukaryotes, they are not considered as fungi, plants, or animals as they follow a different mode of reproduction.

Explanation of Solution

Protists are majorly classified into three types; animal-like, fungi-like, and plant-like protists, based on the mode of nutrient intake. The animal-like protists are also known as protozoans, plant-like protists as algae, and fungi-like protists as molds. 

This basis of broadly classifying protists is quite appropriate as nutrition is a process that occurs in every organism and each mode of nutrition intake categorise broad range of organisms. These categories also classify protists with similar properties as similar body type and structure generally follow common mode of nutrition.

Method of movement. Movement or mobility is the process of how an organism moves from one to another location. Organisms follow different mode movement while others remain sessile and do not move at all. Many organisms may follow a similar mode of movement and yet possess many major differences. Thus, this criterion cannot be used to classify protists.

Type of reproduction. Reproduction is the process of the formation of new organisms from the existing ones. Majorly reproduction is of two types, sexual and asexual. The majority of protists follow the asexual mode of reproduction but yet possess many major differences. Thus, this criterion cannot be used to classify protists.

Type of respiration. Respiration is the process of breaking down complex substances to obtain energy and there is not major variation in respiration process among protists. Therefore, it is not a major mode of categorizing protists.

Conclusion

Classifying protists on the basis of nutrition is appropriate as similar body type and structures follow common mode of nutrition.